One of the great strengths of the prodigious lunchtime theatre A Play, A Pie And A Pint is its capacity to pop up with unexpected gems. One such surprise package is Alan Bissett’s One Thinks Of It All As A Dream. A bio-play about Pink Floyd, touring as part of the Scottish Mental Health Arts and Film Festival, it focuses primarily on the troubled life of the legendary band’s first lead singer and principal songwriter Syd Barrett.

Played out on designer Jonathan Scott’s simple set (a small music gig stage with the interior of a lava lamp projected onto the wall), the piece traces Barrett’s descent into what is widely believed to have been drug-induced mental illness. However, that conventional wisdom is called into question in one humorous scene in which Barrett’s childhood friend, Floyd bass player Roger Waters, meets R.D. Laing. The famous psychiatrist suggests that it may well be the music industry and the band that are dysfunctional, rather than Barrett.

We see Barrett remembering being read The Wind In The Willows by his father, who died when the musician was young. The reappearance of animals from Kenneth Grahame’s children’s book as purveyors of LSD is a smart conceit; it reflects meaningfully on both Barrett’s mental state and the hallucinogenic qualities of the drug.

Bissett explores the concern and frustration of Barrett’s fellow band members, and the serious impact the lead singer’s behaviour began to have on Pink Floyd. In one particularly sad and comical scene, Barrett screws up an early opportunity for the band to make it in the States, becoming a virtual statue on the set of The Pat Boone Show.

Director Sacha Kyle’s production taps in nicely to the ebbs and flows of Bissett’s script, which is at its strongest in the poetic monologues in which Barrett explains his thought processes. Euan Cuthbertson gives a compellingly vulnerable-yet-thoughtful performance as Barrett, while Andrew John Tait deftly walks a tightrope between loyalty and exsaperation as Waters. Both are assisted wonderfully by excellent wigs and costumes.

There are a few moments in which the sometimes cartoonish hyperrealism of the piece becomes a little excessive; for instance, a Stetson-wearing, cowboy booted Texan record company executive is particularly silly. Such moments are few, however, and do little to detract from what is a beautifully honed and truly evocative mini-drama.

Going back, not to the Sixties, but to 1936 is The Broons, a new “play with songs” celebrating the 80th anniversary of Scotland’s iconic cartoon strip family. Written by experienced Scottish dramatist Rob Drummond (Mr Write, Bullet Catch) and directed by Andrew Panton (artistic director of Dundee Rep), the show has been created unashamedly “for the fans”.

Which is not to say that it is caught in 1930s aspic. Although Maw, Paw, The Twins and the rest of the gang seem to emerge from a sugar-coated past, Drummond does make a few concessions to modernity. In particular, like most 21st-century families, The Broons are well-connected to the internet; Hen and Joe, for example, are searching for love online on the dating website Lumber.

In fact, the core of Drummond’s narrative is that the modern world is threatening the future of the Broon family; whether it be the ease of relocating to England, or of flying off to Australia, or, even, of contemplating (as young Horace does) joining an expedition to Mars. As the famous family cohesion is called into question, we watch each Broon spin off in an individual existential crisis.

If that all sounds a bit miserable, worry not. Not only is Becky Minto’s set dominated by the bubble letters BROONS, resplendent in huge, red soft furnishing, but we are treated to oodles of classic Broons, intra-family humour. Add to that various topical gags (not least at the expense of soap opera River City), and cheer is maintained.

There is a dark aspect to the play nevertheless. Spooked by the threat of her multitudinous offspring flying the nest, Maw Broon becomes an implausibly devious cross between Ma Walton and Dick Dastardly. Formidable Maw may be, but her underhand tactics here stretch one’s credulity to breaking point.

In the end, Drummond and Panton resolve the play’s tensions in an entirely predictable, sickly sweet nostalgia, complete with a medley of pop hits built around the Bay City Rollers’ Shang-A-Lang. When the talented cast (which includes Still Game’s Paul Riley and award-winning actor Kevin Lennon) roused the audience to a frenzy of dancing and singing along, I confess, I felt like Bernie Sanders at a Donald Trump rally.

The Broons is crowd-pleasing stuff for its target audience, without question. However, given Drummond’s undoubted talent, one would expect more than this theatrical equivalent of painting-by-numbers.